This invention relates to a filter with a filter cassette, which is disposed in a filter housing and which includes a fanfolded filter medium extending in one plane, with side members formed by thin walled outer strips and cemented against the two staggered faces of the filter medium. Furthermore, the invention relates to a process for manufacturing such a filter and a filter cassette for the filter.
A filter of the above kind is the subject matter of DE-A-31 50 392. In the case of the known filter the outer strips cemented on the filter medium have a peripheral edge, which is oriented flange-like towards the outside, and are cemented like a frame against all four narrow sides of the filter medium. The filter medium provided with these outer strips forms a filter cassette, whose flanged edge rests in the mounted state axially against a seal of a holding frame.
The outer strips represent a solid frame. Therefore, they must be designed so stable that they can carry the filter medium, when its outwardly oriented, flanged edge is clamped into a holding frame. Thus, they cannot be made of the same material as the filter medium. The frame formed by the outer strips must also be disposed of when the filter medium is changed. Another drawback of the known filter cassette is that its mounting in a holding frame and the cementing of the outer strips against the four narrow sides of the filter medium is relatively time consuming.